In devices for mounting and dismounting machine parts onto and from shafts, it is known to separate the shaft and ring connection using a tool having support legs which press against the ring that is to be pulled away, see for example German Patent publication No. DE 30 17 595 A1. However, all known puller devices of this type cannot be used with the drive shaft of a motor's drive unit if the plug-in pinion has a conical shaft which is inserted in a similarly conical seating bore in the motor's drive shaft. This type of drive unit therefore requires a special tool.
In directly-driven toothed gears operating without a clutch, the torque transmission from the motor to the gear is typically accomplished (1) through toothing cut out on the motor shaft, (2) through a pinion mounted on the motor shaft, or (3) through a pinion inserted into the motor shaft, also known as a "plug-in pinion".
While the first design mentioned is useful only for constant transmissions of the primary stage and, even then, for reasons of geometry, only for a limited transmission range, the second and third torque transmission designs allow greater transmission variation as well as subsequent modification of the transmission through exchange of the toothed parts.
The transmission of power in the second and third designs mentioned above can occur through material connection (bonding, soldering, etc.), through frictional connection (longitudinal press, shrink press, and expansion press connections, etc.), or through a combination of these two connection types.
Naturally, positive-locking solutions, such as installed adjusting springs, for example, are also possible.
When mounted pinions are used, only rarely can high transmissions be achieved in the primary stage because the diameter of the motor shaft is sharply limited. Consequently, the plug-in pinion design permits a significantly larger transmission range to be covered. However, plug-in pinions of this type typically are more expensive due to their plug-in pinion connection. While mounted pinions can usually be easily mounted through heating and easily dismounted with the help of a simple puller device, the plug-in pinion connection requires more expensive work steps and tools for both insertion and removal.